Jtextarea不显示文本

Question

i create in my project a jform on netbeans on Mac , I create him automatically with the drag & drop ,`I put Three button and one jtextarea. In the main of the project I create a new object of the type of this jform. the jform appear but the text in the jtextarea don't appear.

netbeans create automatically initcomponent like this :

private void initComponents() {

    jButton1 = new javax.swing.JButton();
    jButton2 = new javax.swing.JButton();
    jButton3 = new javax.swing.JButton();
    jButton4 = new javax.swing.JButton();
    jScrollPane1 = new javax.swing.JScrollPane();
    jTextArea1 = new javax.swing.JTextArea();

    setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

    jButton1.setText("reply");
    jButton1.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            jButton1ActionPerformed(evt);
        }
    });

    jButton2.setText("reply-all");

    jButton3.setText("delete");

    jButton4.setText("forward");

    jTextArea1.setColumns(20);
    jTextArea1.setRows(5);
    jScrollPane1.setViewportView(jTextArea1);

    javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
    getContentPane().setLayout(layout);
    layout.setHorizontalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(layout.createSequentialGroup()
            .addContainerGap()
            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
                .addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 363, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addGroup(layout.createSequentialGroup()
                    .addComponent(jButton1)
                    .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                    .addComponent(jButton2)
                    .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                    .addComponent(jButton3)
                    .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                    .addComponent(jButton4)))
            .addContainerGap(23, Short.MAX_VALUE))
    );
    layout.setVerticalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(layout.createSequentialGroup()
            .addContainerGap()
            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                .addComponent(jButton1)
                .addComponent(jButton2)
                .addComponent(jButton3)
                .addComponent(jButton4))
            .addGap(18, 18, 18)
            .addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 232, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addContainerGap(15, Short.MAX_VALUE))
    );

    pack();
}

i create the constructor like this :

public MailRead(Email a){
    java.awt.EventQueue.invokeLater(() -> {
        new MailRead().setVisible(true);
    });
    Date d=new Date();
    this.a=a;
    a=new Email("ffd", "edgvxsfz", "h6v4gtrwd","ujyhrstegfw", d,21334231);
    initComponents();

    //System.out.println("-----Email from : "+a.getMittente()+"-----"+"\n"+"-----Object : "+a.getObj()+"-----\n"+a.getEmail());
    String text= "-----Email from : "+a.getMittente()+"-----"+"\n"+"-----Object : "+a.getObj()+"-----\n"+a.getEmail();

    jTextArea1=new JTextArea(text);
}

the email code is this :

import java.io.Serializable;
import java.util.Date;

public class Email implements Serializable{
    String mittente;
    String destinatario;
String email;
Date dataInvio;
int id;
String obj;
boolean isnew;

public Email(String mittente, String destinatario,String obj, String email, Date dataInvio,int id) {
    this.mittente = mittente;
    this.destinatario = destinatario;
    this.email = email;
    this.dataInvio = dataInvio;
    this.id=id;
    this.obj=obj;
    isnew=true;
}

public String getMittente() {
    return mittente;
}

public void setMittente(String mittente) {
    this.mittente = mittente;
}

public String getDestinatario() {
    return destinatario;
}

public void setDestinatario(String destinatario) {
    this.destinatario = destinatario;
}

public String getEmail() {
    return email;
}

public void setEmail(String email) {
    this.email = email;
}

public String getObj() {
    return obj;
}

public void setObj(String obj) {
    this.obj = obj;
}

public Date getDataInvio() {
    return dataInvio;
}


public void setDataInvio(Date dataInvio) {
    this.dataInvio = dataInvio;
}

public int getId() {
    return id;
}

public boolean isIsnew() {
    return isnew;
}

public void setIsnew(boolean isnew) {
    this.isnew = isnew;
}

@Override
public String toString() {
    return "Email{" + "mittente=" + mittente + ", destinatario=" + destinatario + ", email=" + email + ", dataInvio=" + dataInvio + ", id=" + id + '}';
}

} in the contractor I assigned value at the moment in the real code I use the parameters of MailRead how can solve to read the email in jtextarea ?

Answer 1

jTextArea1=new JTextArea(text);

Don't create a new JTextArea.

You want to add text to the existing text area that has been added to the frame. So you would use:

jTextArea1.append(text);

This means when you create your MailRead class you need to pass the text area as a parameter to the MailRead class as well as the Email parameter so your MailRead` class can append text to the text area.